1. Field of the Invention
The present invention relates to an automatic sound volume controller for use with an on-vehicle audio equipment.
2. Description of the Related Art
Inside a running vehicle, the operator feel as if the reproduced sounds from speakers of the onboard audio equipment were reduced in volume. This phenomenon is caused by the masking of the sounds by the noises coming into the cabin in running state.
A typical solution to the lowered sound volume inside the cabin is to add effect sounds such as a simulated reflection to the sounds reproduced by the onboard audio equipment. Because the level of the effect sounds is lower than that of the direct sounds from the speakers, the added effect sounds still tend to be masked by the noises emanating from the vehicle that is running. This negates the objective in adding the sound effects to the audio signal.
Raising the level of the effect sounds in advance has failed to solve the problem. The reason is that whenever the vehicle comes to a temporary stop on the road, the passengers inside get an unpleasant acoustic sensation from the excessively added effect sounds.